Currently, I use a Feathered Friends Lark that I had custom made in 1998 (picked colors, 2oz overfill, and used their version of "gore lite" on the shell - some type of PTFE laminate).The bag has been outstanding and looks new after 11 years, but it is a bit heavy at just under 3 lbs for a 10 degree bag (maybe 5 degree with the overstuffing). I use the exped downmat 9 for a pad.

I'd like to lighten this system. I've considered the Big Agnes Zirkel bag and a Pacific outdoor equipment Ether Thermo 6 pad. The zirkel weighs 1 lb 14oz, and the pad weighs 1 lb 5oz making the system much lighter for me. Has anyone used the Big Agnes bags - or, I should say system since they require a pad since the bags have no insulation on the bottom? The weight on this system looks great but since I rarely see Big Agnes mentioned, I'd assume there is a good reason why everyone opts for Marmot, Western, Valandre, etc.? Thanks for any advice, and for this great forum. I'm a long term lurker who is just recently posting....thanks again.

The Good -- A few years ago, I tried out BA's bag/air core pad combo system at my local gear store and found it extremely comfortable. BA's bottom sleeve design makes sense to me.

The Not So Good -- Whatever weight BA took away by eliminating the bottom insulation -- it more than added back by sizing its bags bigger than most. So, if you are of slight to medium build -- you can find lighter bags with the same given warmth -- such as Western Mountaineering or MontBell. But then, even if you are a big guy -- you can still go with MontBell's superstretch bags and save weight over BA.

Finally, no direct experience, but I've read that BA's bag warmth ratings are a bit on the optimistic side. While warmth is subjective, most readers report fairly accurate warmth ratings for MontBell -- and conservative warmth ratings for Western Mountaineering.

The good: I love the system. I am a side, stomach, back sleeper and roll all night. Being able to do so in the sack without falling off the pad is WONDERFUL. Their customer service, at least from a product question stand point, is awesome. Really nice, responsive and personable. Bag quality seems good, on par with most imported bags particularly in the higher end bags. Not WM, but nowhere near the cost.

The bad: Although I'm not the best judge of temp because I am a freakishly cold sleeper, I think they are somewhat optimistic in their temperature ratings. In particular, sleeping directly on an insulated air core was a very cold experience for me in the 20s with a 0 degree bag. Those large sidewalls seem to let the pad chill down quite a bit. If you go with their mummy bag, you MUST use their pad which are either heavy for the warmer ones or cold for me. I haven't tried a POE so that might work but REI's Lite-Core doesn't nor does the Prolite or at least not without odd stuffing or folding. If the pad doesn't fit correctly, you can leave gaps of just nylon rather than pad or insulation allowing heat to seep out.

I think the functional girth is not as large as the specs indicate. Stuffing the pad in the sleeve stretches the bag out and makes for a tighter fit than you'd think given the dimensions.

Like I said, I sleep WAY cold so my temperature experiences are probably extreme compared to the "average" user. I chose to get rid of mine and invest in a -10 WM bag for all around use. No joke. Our scoutmaster has a -20 and complained of cold at ten degrees but I don't know what he was using for a pad. My friend recently bought a Lost Ranger semi-rectangular pad rated for 15 degrees and was fine in the temperatures I was cold in while also using an IAC pad so ymmv.

If I could make it work, I'd still be using it due to the fixed pad thing but I need to make sure I keep warm and don't think I can get a bag from them matching the weight of the WM that will provide the same warmth.

I currently use a Big Agnes Lost Ranger (long) with the air core pad (long). I LOVE the BA system. I was skeptical about it at first but it is the most comfortable system I've ever slept with. I've talked to people who hate them too. They say the sleep system as a whole is too heavy or they don't like that there is no insulation on the bottom of the bag and therefore pretty much HAVE to use a pad, etc.. But it works for me and I really like the system. I was pretty much stuck on the system after I used it for the first time.

I've also found that you can substitute the BA air core for a thermarest or closed cell foam pad and it fits just fine if you are worried about the weight of the BA pad. I messed around with it in my garage with my thermarest and with a ridgerest pad and they work just fine.

For fit, I was talking about the true mummy bags, not the Lost Ranger which will take any square pad. The mummy styles have a very specific angled pad size. I'd try a POE before committing. The REI Lite Core wouldn't go in properly to mine.

Like most above I loved the system. It was convenient, and being a side and stomach sleeper it was great having the extra room.

The problems I had were two fold. With the encampment the packed size was so large it was comical. I went canoeing through the everglades in January and even with a canoe the size was silly. If I hadn't remembered my days with coleman synthetic bags I would have thought that a packed bag couldnt get any larger.

With the ripple creek the issue was the temp rating. At 35*, with poly long underwear, my fleece coat, a liner and the bag I was so cold I couldnt sleep until the sun came up. I had eaten a large meal and got out of the bag to boil some water to warm up twice and at no point did I feel comfortable in it. Again the packed size was large.

Finally, and this is just a nit-pick by me, the bag just wasn't comfortable to be in. I don't know if it was the material, or the size (you CAN fall off the pad inside the bag, or so I found), or just the general dislike of the bag oveall clouding my opinion I am not sure.

I switched to a Sierra Designs Arrow Rock 15* down bag and couldn't be happier with the decision. I know it not really fair to compare down to synthetic, but I am. It has the stretch system used it the superstretch bags, pad straps to keep it on the pad and packs smaller and light that the BA bags did.

As stated above, I really liked the BA system of "anchoring" the bag to the pad. I copied this system by sewing loops and then attaching two straps onto my beloved MontBell bag -- and it worked beautifully. No sliding off the pad and no "cold spots" when turning from one side to the other.

I have one of the new Zirkels (long) and use it with an Insulated Air Core pad.

My weight is right on with their claims. The down is very nice. I have had it down to 30 F but am a side sleeper so I do not get all the warmth I should from these bags. If you sleep on your back it should do you good.

Thanks for the advice. I have purchased several sleeping bags, and will return all but one. The choice is down to the zirkel, alpinlite, or versalite. I'm 5'9" and about 185 with an athletic build so I have to find a bag with about 62" girth to be comforatble, other wise I'd be considering the phantom, ultralite, etc.

I will also give the Pacific outdoor equipment Ether Thermo 6 pad a try. I certainly do not expect it to be as warm as my exped downmat 9, but I hope it is adequate for 25 degrees with the selected bag. Any advice on any better alternatives than the Ether thermo 6 are welcomed (with approximately the same comfort). I selected it over the Big Agnes insulated air core because I have read many subjective accounts that the PAC pad is slightly warmer.

Brian, given your comments about your old FF bag... I wouldn't hesitate to get either WM. If you're shooting for 20 degree-ish, know that WM is quite conservative w/their ratings. BA is overly optimistic with their ratings. Given the appreciation you've expressed for your FF bag, grab the AlpinLite.

Shoot, if you're going for more of a 3-season bag, you might even consider the 30*F MegaLite at 24 ounces. My similarly-rated SummerLite (just narrower cut) takes my cold-sleeping carcass comfortably to those ranges, with room to add a down jacket or something as needed... But if you want a bit more warmth/safety margin, the other bags are great, light options.

“I've never figured out what the bottom of the bags are like. Are they completely uninsulated? Or is there any insulation in the footbox area?”

Tom, here is a description of the system from a review I wrote.

The bottom of the bag has a double layer of shell material creating a “sleeping pad pocket”. The bag has no insulation on the bottom, instead relying on the pad to provide it. A 20 x 78 in (50 x 195 cm) mummy-shaped sleeping pad is inserted into the sleeve. As the pad is in the sleeve there is no chance of the bag slipping off the pad.

The side of the bag away from the zipper continues down past the edge of the pad pocket to prevent cold spots. To do the same under the zipper a down filled “No-draft” wedge insulates the connection between the sleeve and the zipper. It is backed by a wide piece of nylon to keep the zipper from getting stuck.